What It Would Be Like to Live on Uranus' Moons Titania and Miranda What It Would Be Like to Live on Uranus' Moons Titania and Miranda by Joseph Castro, Space.com Contributor Share View photos The surface of Uranus' moon Miranda (seen here) is pocked with craters, but humans might be able to find a way to settle it. The image was taken during Voyager 2's flyby of the Uranus system in 1986. More Uranus would be a fascinating planet to visit, but living there would be extremely difficult. However, its moons are a different story. In all, Uranus has 27 known moons , and its five largest satellites are often considered its "major moons." If we wanted to set up permanent bases on Uranus's satellites, Titania and Miranda are great targets — Titania presents the strongest gravity (almost 4 percent of Earth's), and Miranda has a surface ripe for exploration. Because Voyager 2 is the only spacecraft to visit the Uranus system, Earthlings still don't know much about the planet's moons.

"When [ Voyager 2 ] flew past in 1986, it was winter and dark on the whole northern hemispheres of all the moons, so we could only see a portion of their southern hemispheres," Jeff Moore, a planetary scientist at NASA Ames Research Center in California said. "The encounter was also a bit like flying through a bull's-eye. Rather than one moon at a time, [Voyager 2] encountered the whole system at once." [ How to live on one of Uranus' moons (Infographic) ] Images from Voyager 2 show that Titania's southern hemisphere has numerous craters and tectonic landforms, including canyons and faults, some of which could be interesting locations to visit. The largest crater on Titania is about 203 miles (326 kilometers) across, and its longest canyon extends over 930 miles (1,500 km) from its equator almost to its south pole. The surface of Miranda, on the other hand, is incredibly varied and jumbled, resembling a jigsaw puzzle that wasn't pieced together correctly. It sports odd formations called coronae, which are oval grooved structures resembling racetracks.

It also has cratered plains that are crisscrossed with huge canyons and faults. Some of Miranda's fault cliffs are about 12 times as deep as the Grand Canyon. Because of Miranda's very low gravity (less than 1 percent of Earth's), a rock dropped from the top of the cliff would take about 10 minutes to reach the bottom. These faults could provide fun for thrill-seekers. "I think it would be a little dangerous, but if we lived on Miranda there would probably be a few daredevils wanting to jump off the cliffs," Moore told Space.com. All of Uranus' moons lack weather, sky colors and surface pressure due to non-existent atmospheres. They are also very cold: the average temperature of Titania, for example, is about minus 334 Fahrenheit (minus 203 Celsius). Aside from the deadly cold, it's not clear what kinds of dangers you'd experience on the moons. They may have moonquakes, as well as cryovolcanism that could shake the ground.

Intense radiation from charged particles produced by Uranus's magnetosphere could also pose a problem, especially if you lived on the side of the moons facing away from the planet (one side of Titania and Miranda face Uranus at all times). Titania takes almost nine Earth days to rotate on its axis, while Miranda takes about 1.4 days. If you lived at the equator of these moons, you could experience a "normal" day-night cycle, but the same isn't true for the poles. Unlike other planets in the solar system, Uranus has an axial tilt of about 98 degrees. This means that during the planet's 84-Earth-year-long trip around the sun, the poles of Uranus and its moons experience 42 years of sunlight followed by 42 years of darkness. If you looked at the sun through a filter from Titania or Miranda, it would appear as a very small disk and not just a point of light, Moore said. And if you were on the side of the moons facing Uranus, the planet would be huge — Uranus would be about 41 times the size of our moon from Miranda, and about half that size from Titania.

You could also see the other major moons of Uranus from the surface of Titania and Miranda. "All would form an appreciable disk in the sky," Moore said. And if you wanted to email a photo of Uranus or its moons to your friends and family back home, that radio signal would take, on average, about 2.5 hours to reach Earth . Editor's Note: This part of Space.com's 12-part series " Living on Other Planets: What It Would Be Like " to see what an astronaut would see on other planets and moons of our solar system and beyond. Check back each Tuesday to see what humans might encounter on other cosmic bodies in the universe. What It Would Be Like to Live on Uranus' Moons Titania and Miranda What It Would Be Like to Live on Uranus' Moons Titania and Miranda By Joseph Castro, Space.com Contributor | March 17, 2015 07:01am ET MORE The surface of Uranus' moon Miranda (seen here) is pocked with craters, but humans might be able to find a way to settle it. The image was taken during Voyager 2's flyby of the Uranus system in 1986.

Credit: NASA Uranus would be a fascinating planet to visit, but living there would be extremely difficult. However, its moons are a different story. In all, Uranus has 27 known moons , and its five largest satellites are often considered its "major moons." If we wanted to set up permanent bases on Uranus's satellites, Titania and Miranda are great targets — Titania presents the strongest gravity (almost 4 percent of Earth's), and Miranda has a surface ripe for exploration. Because Voyager 2 is the only spacecraft to visit the Uranus system, Earthlings still don't know much about the planet's moons. "When [ Voyager 2 ] flew past in 1986, it was winter and dark on the whole northern hemispheres of all the moons, so we could only see a portion of their southern hemispheres," Jeff Moore, a planetary scientist at NASA Ames Research Center in California said. "The encounter was also a bit like flying through a bull's-eye.

Rather than one moon at a time, [Voyager 2] encountered the whole system at once." [ How to live on one of Uranus' moons (Infographic) ] Titania, an airless moon of Uranus, is cold and its day is 84 years long. See what it would be like for an astronaut on Titania in this full infographic . Credit: by Karl Tate, Infographics Artist Images from Voyager 2 show that Titania's southern hemisphere has numerous craters and tectonic landforms, including canyons and faults, some of which could be interesting locations to visit. The largest crater on Titania is about 203 miles (326 kilometers) across, and its longest canyon extends over 930 miles (1,500 km) from its equator almost to its south pole. The surface of Miranda, on the other hand, is incredibly varied and jumbled, resembling a jigsaw puzzle that wasn't pieced together correctly. It sports odd formations called coronae, which are oval grooved structures resembling racetracks. It also has cratered plains that are crisscrossed with huge canyons and faults.

Some of Miranda's fault cliffs are about 12 times as deep as the Grand Canyon. Because of Miranda's very low gravity (less than 1 percent of Earth's), a rock dropped from the top of the cliff would take about 10 minutes to reach the bottom. These faults could provide fun for thrill-seekers. "I think it would be a little dangerous, but if we lived on Miranda there would probably be a few daredevils wanting to jump off the cliffs," Moore told Space.com. All of Uranus' moons lack weather, sky colors and surface pressure due to non-existent atmospheres. They are also very cold: the average temperature of Titania, for example, is about minus 334 Fahrenheit (minus 203 Celsius). This image of Titania, taken by the Voyager 2 probe, shows the cratered surface of Uranus' moon. Credit: NASA Aside from the deadly cold, it's not clear what kinds of dangers you'd experience on the moons. They may have moonquakes, as well as cryovolcanism that could shake the ground.

Intense radiation from charged particles produced by Uranus's magnetosphere could also pose a problem, especially if you lived on the side of the moons facing away from the planet (one side of Titania and Miranda face Uranus at all times). Titania takes almost nine Earth days to rotate on its axis, while Miranda takes about 1.4 days. If you lived at the equator of these moons, you could experience a "normal" day-night cycle, but the same isn't true for the poles. Unlike other planets in the solar system, Uranus has an axial tilt of about 98 degrees. This means that during the planet's 84-Earth-year-long trip around the sun, the poles of Uranus and its moons experience 42 years of sunlight followed by 42 years of darkness. If you looked at the sun through a filter from Titania or Miranda, it would appear as a very small disk and not just a point of light, Moore said. And if you were on the side of the moons facing Uranus, the planet would be huge — Uranus would be about 41 times the size of our moon from Miranda, and about half that size from Titania.

The butt of solar system jokes, Uranus is also a spectacular blue planet still hiding many scientific secrets. See how much you know: Start Over | More Quizzes You could also see the other major moons of Uranus from the surface of Titania and Miranda. "All would form an appreciable disk in the sky," Moore said. And if you wanted to email a photo of Uranus or its moons to your friends and family back home, that radio signal would take, on average, about 2.5 hours to reach Earth . Editor's Note: This part of Space.com's 12-part series " Living on Other Planets: What It Would Be Like " to see what an astronaut would see on other planets and moons of our solar system and beyond. Check back each Tuesday to see what humans might encounter on other cosmic bodies in the universe. Follow Joseph Castro on Twitter . Follow us @Spacedotcom , Facebook and Google+ . Original article on Space.com . Editor's Recommendations Moons Moons: Moons are `fossils" into a planet's past.

The major, named moon systems are: Earth: Luna (The Moon) Mars: Deimos, Phobos Jupiter: Adrastea, Amalthea, Ananke, Callisto, Carme, Elara, Europa, Ganymede, Himalia, Io, Leda, Lysithea, Metis, Pasiphae, Sinope, Thebe Saturn: Atlas, Calypso, Dione, Enceladus, Epimetheus, Helene, Hyperion, Iapetus, Janus, Mimas, Pan, Pandora, Phoebe, Prometheus, Rhea, Telesto, Tethys, Titan Uranus: Ariel, Belinda, Bianca, Cordelia, Cressida, Desdemona, Juliet, Miranda, Oberon, Ophelia, Portia, Puck, Rosalind, Titania, Umbriel Neptune: Despina, Galatea, Larissa, Naiad, Nereid, Proteus, Thalassa, Triton Pluto: Charon (note: Pluto/Charon form a binary system, but Charon is the smaller so it is classed as the moon of Pluto) New, smaller moons are being discovered all the

 time with recent space missions.

The total count of moons (as of 12/18/2001) are: Mercury - 0 moons Mars - 2 moons Uranus - 20 moons Venus - 0 moons Jupiter - 28 moons Neptune - 8 moons Earth - 1 moon Saturn - 30 moons Pluto - 1 moon Moons range in shape from highly irregular to spheres. Their shape reflects their formation history, irregular objects are ill-formed moons (captured asteroids or comets) or pieces of a larger moon, spherical objects were once molten spheres, probably at the time of their formation. Moons of Mars: Deimos & Phobos We speculate, from their irregular appearances and low mean densities, that Deimos and Phobos, are captured asteroids. Both Deimos and Phobos are saturated with craters. Deimos has a smoother appearance caused by partial filling of some of its craters. Moons of Jupiter: Jupiter has 63 confirmed moons as of Jan 2009, i.e. moons with known orbits around Jupiter. Eight of these moons are regular, meaning they have prograde, nearly circular orbits.

They are composed of the four Galilean satellites, plus the inner or Amalthea group: Adrastea is a typical small moon Metis is the innermost known satellite of Jupiter Amalthea is one of Jupiter's smaller, irregular moons, an example of moon collecting dust from another moon (Io) The remaining 55 moons are irregular, they have a mixture of prograde and retrograde orbits with high inclinations and eccentricities. Jupiter's regular satellites are believed to have formed from a circumplanetary disk, a ring of accreting gas and solid debris analogous to a protoplanetary disk. The irregular satellites are substantially smaller objects with more distant and eccentric orbits. They form families with shared similarities in orbit (semi-major axis, inclination, eccentricity) and composition; it is believed that these are at least partially collisional families that were created when larger (but still small) parent bodies were shattered by impacts from asteroids captured by Jupiter's gravitational field. Moons of Saturn: The moons of Saturn are numerous and diverse, ranging from tiny moonlets less than 1 kilometer across to the enormous Titan, which is larger than the planet Mercury.

Saturn has sixty-two moons with confirmed orbits, fifty-three of which have names, and only thirteen of which have diameters larger than 50 kilometers. Saturn has seven moons that are large enough to become spherical. Twenty-four of Saturn's moons are regular satellites; they have prograde orbits not greatly inclined to the Saturn's equatorial plane. These include the seven major satellites, four small moons which exist in a Trojan orbit with larger moons, two mutually co-orbital moons and two moons which act as shepherds of Saturn's F Ring. Two other known regular satellites orbit within gaps in Saturn's rings. The relatively large Hyperion is locked in a resonance with Titan. The remaining regular moons orbit near the outer edge of the A Ring, within G Ring and between the major moons Mimas and Enceladus. The regular satellites are traditionally named after Titans and Titanesses or other figures associated with the mythological Saturn. The remaining thirty-eight, all small except one, are irregular satellites, whose orbits are much farther from Saturn, have high inclinations, and are mixed between prograde and retrograde. These moons are probably captured minor planets, or debris from the breakup of such bodies after they were captured, creating collisional families.

The irregular satellites have been classified by their orbital characteristics into the Inuit, Norse, and Gallic groups, and their names are chosen from the corresponding mythologies. The largest of the irregular moons is Phoebe, the ninth moon of Saturn, discovered at the end of the 19th century. The rings of Saturn are made up of objects ranging in size from microscopic to hundreds of meters, each of which is on its own orbit about the planet. Thus, a precise number of Saturnian moons cannot be given, as there is no objective boundary between the countless small anonymous objects that form Saturn's ring system and the larger objects that have been named as moons. At least 150 moonlets embedded in the rings have been detected by the disturbance they create in the surrounding ring material, though this is thought to be only a small sample of the total population of such objects. Daphnis drifts through the Keeler gap Atlas the second of Saturn's known satellites, orbits near the outer edge of the A-ring Enceladus is one of the innermost moons of Saturn.

Enceladus reflects almost 100 percent of the sunlight that strikes it and has evidence of internal heating and recent resurfacing effects Hyperion is one of the smaller moons of Saturn. It has a pock-marked body and is the largest irregularly shaped satellite ever observed.

Iapetus is one of the stranger moons of Saturn, its leading side is dark with a slight reddish color while its trailing side is bright Dione is the densest moon of Saturn other than Titan, and has several usual characteristics: 1) has a rocky core and ice crust, 2) is heavy cratering on trailing hemisphere, 3) has bright, wispy features Rhea is the largest airless satellite of Saturn that has different regions with different crater sizes indicating that parts of the moon have undergone resurfacing since formation Mimas is one of the innermost moons of Saturn with a very large impact crater that came close to fracturing the moon Tethys is an icy body similar in nature to Dione and Rhea Phoebe is the last of the known satellites of Saturn and orbits in a retrograde direction (opposite to the direction of the other satellites' orbits) in a plane much closer to the ecliptic than to Saturn's equatorial plane. Thus, Phoebe may be a captured asteroid with a composition unmodified since the time it was formed in the outer Solar System.

Moons of Uranus: Uranus, the seventh planet of the Solar System, has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other spherical moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda). The remaining moons were discovered after 1985, either during the Voyager 2 flyby mission or with the aid of advanced Earth-based telescopes. A montage of Uranus' large moons and one smaller moon: from left to right Puck, Miranda, Ariel, Umbriel, Titania and Oberon. Uranian moons are divided into three groups: thirteen inner moons, five major moons, and nine irregular moons. The inner moons are small dark bodies that share common properties and origins with the planet's rings. The five major moons are massive enough to have achieved hydrostatic equilibrium (they were once molten spheres), and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces.

The largest of these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about 20 times less massive than Earth's Moon. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at great distances from the planet. Ariel is a relatively small satellite and is the brightest moon of Uranus Miranda with a jumbled surface unlike anything in the Solar System, indicates evidence of violent past with possible multiple shattering and reassembly Titania is the largest moon of Uranus and is marked by a few large impact basins Moons of Neptune: Neptune has thirteen known moons, by far the largest of which is Triton, discovered by William Lassell just 17 days after the discovery of Neptune itself. Over a century passed before the discovery of the second natural satellite, called Nereid. Neptune's moons are named for minor water deities in Greek mythology. Unique among all large planetary moons, Triton is an irregular satellite, as its orbit is retrograde to Neptune's rotation and inclined relative to the planet's equator.

The next-largest irregular satellite in the Solar System, Saturn's moon Phoebe, is only 0.03% Triton's mass. Triton is massive enough to have achieved hydrostatic equilibrium and to retain a thin atmosphere capable of forming clouds and hazes. Both its atmosphere and its surface are composed mainly of nitrogen with small amounts of methane and carbon monoxide. Triton's surface appears relatively young, and was probably modified by internally driven processes within the last few million years. The temperature at its surface is about 38K. Inward of Triton are six regular satellites, all of which have prograde orbits in planes that lie close to Neptune's equatorial plane. Some of these orbit among Neptune's rings. The largest of them is Proteus. Neptune also has six outer irregular satellites, including Nereid, whose orbits are much farther from Neptune, have high inclinations, and are mixed between prograde and retrograde. The two outermost ones, Psamathe and Neso, have the largest orbits of any natural satellites discovered in the Solar System to date.

Proteus is one of the darkest objects in the Solar System What It Would Be Like to Live on Uranus' Moons Titania and Miranda -RocketNews Posted on April 3, 2015 by Editor - Science News Uranus would be a fascinating planet to visit, but living there would be extremely difficult. However, its moons are a different story. In all, Uranus has 27 known moons , and its five largest satellites are often considered its “major moons.” If we wanted to set up permanent bases on Uranus’s satellites, Titania and Miranda are great targets — Titania presents the strongest gravity (almost 4 percent of Earth’s), and Miranda has a surface ripe for exploration. Because Voyager 2 is the only spacecraft to visit the Uranus system, Earthlings still don’t know much about the planet’s moons. “When [ Voyager 2 ] flew past in 1986, it was winter and dark on the whole northern hemispheres of all the moons, so we could only see a portion of their southern hemispheres,” Jeff Moore, a planetary scientist at NASA Ames Research Center in California said. “The encounter was also a bit like flying through a bull’s-eye.

Rather than one moon at a time, [Voyager 2] encountered the whole system at once.” [ How to live on one of Uranus’ moons (Infographic) ] Images from Voyager 2 show that Titania’s southern hemisphere has numerous craters and tectonic landforms, including canyons and faults, some of which could be interesting locations to visit. The largest crater on Titania is about 203 miles (326 kilometers) across, and its longest canyon extends over 930 miles (1,500 km) from its equator almost to its south pole. The surface of Miranda, on the other hand, is incredibly varied and jumbled, resembling a jigsaw puzzle that wasn’t pieced together correctly. It sports odd formations called coronae, which are oval grooved structures resembling racetracks. It also has cratered plains that are crisscrossed with huge canyons and faults. Some of Miranda’s fault cliffs are about 12 times as deep as the Grand Canyon. Because of Miranda’s very low gravity (less than 1 percent of Earth’s), a rock dropped from the top of the cliff would take about 10 minutes to reach the bottom.

These faults could provide fun for thrill-seekers. “I think it would be a little dangerous, but if we lived on Miranda there would probably be a few daredevils wanting to jump off the cliffs,” Moore told Space.com. All of Uranus’ moons lack weather, sky colors and surface pressure due to non-existent atmospheres. They are also very cold: the average temperature of Titania, for example, is about minus 334 Fahrenheit (minus 203 Celsius). Aside from the deadly cold, it’s not clear what kinds of dangers you’d experience on the moons. They may have moonquakes, as well as cryovolcanism that could shake the ground. Intense radiation from charged particles produced by Uranus’s magnetosphere could also pose a problem, especially if you lived on the side of the moons facing away from the planet (one side of Titania and Miranda face Uranus at all times). Titania takes almost nine Earth days to rotate on its axis, while Miranda takes about 1.4 days. If you lived at the equator of these moons, you could experience a “normal” day-night cycle, but the same isn’t true for the poles.

Unlike other planets in the solar system, Uranus has an axial tilt of about 98 degrees. This means that during the planet’s 84-Earth-year-long trip around the sun, the poles of Uranus and its moons experience 42 years of sunlight followed by 42 years of darkness. If you looked at the sun through a filter from Titania or Miranda, it would appear as a very small disk and not just a point of light, Moore said. And if you were on the side of the moons facing Uranus, the planet would be huge — Uranus would be about 41 times the size of our moon from Miranda, and about half that size from Titania. You could also see the other major moons of Uranus from the surface of Titania and Miranda. “All would form an appreciable disk in the sky,” Moore said. And if you wanted to email a photo of Uranus or its moons to your friends and family back home, that radio signal would take, on average, about 2.5 hours to reach Earth .

Editor’s Note: This part of Space.com’s 12-part series “ Living on Other Planets: What It Would Be Like ” to see what an astronaut would see on other planets and moons of our solar system and beyond. Check back each Tuesday to see what humans might encounter on other cosmic bodies in the universe. Miranda, moon of Uranus - The Solar System on Sea and Sky Voyager 2 mosaic image of Miranda showing unique features (NASA/JPL) Daughter of Prospero Miranda [mih-RAN-dah] is the eleventh of Uranus' moons and is the fifth largest. It is the smallest and innermost of the planet's five major moons and is without a doubt the most interesting. Miranda was named after the daughter of the magician Prospero in Shakespeare's The Tempest. Unlike the other moons in the Solar System, which are named after Greek an Roman mythological figures, the moons of Uranus are named after characters from classic literature. Miranda was discovered by Gerard Kuiper in 1948. Nearly everything we know about this moon was learned from the Voyager 2 encounter in 1986.

Voyager 2 close-up of Miranda showing the chevron feature (NASA/JPL) (NASA/JPL) A Cosmic Jigsaw Puzzle Miranda is unlike any other body in the Solar System. Its surface is a jumbled assortment of curious terrains. Miranda is thought to be composed of about water ice and half rocky material. The temperature of this icy world averages just -335 F (-187° C). Astronomers had expected this moon to show little or no history of internal activity, much like Jupiter's moon Callisto. But when the images came back from the Voyager 2 probe, everyone was amazed by what they saw. Miranda looks almost as if several different pieces of rock were glued together in a random fashion. There are huge faults, deep canyons, steep cliffs, smooth plains, and curiously shaped rifts. Astronomers once believed that Miranda had been shattered to pieces and reassembled several times throughout its long history. But more recent theories suggest that the upwelling of partially melted ices may be responsible for these curious surface features. The real reason is still a mystery.

This close-up image of Miranda was taken by the Voyager 2 spacecraft at an altitude of 22,OOO miles (36,OOO km). The image clearly shows Miranda's diverse surface features and terrain types. (NASA/JPL) Features of Miranda One of the most remarkable features on Miranda is known as the "chevron". It is a series of light and dark grooves arranged in a v-shape. This large feature dominates most images of the moon. Miranda also contains fault canyons as deep as 12 miles (20 km) deep. This is a deep canyon for a moon that is only 290 miles (470 km) in diameter. Several faults crisscross the valleys and ridges on Miranda. Some of these faults produce steep cliffs, or fault scarps. The largest of these cliffs is 3 miles (5 km) high, nearly three times as high as the walls of the Grand Canyon on Earth. The rest of Miranda's surface is littered with grooves and craters. Many of these have exposed underlying material with a different albedo. Some of these ridges have been referred to as "layer cakes" or "race tracks" due to their unusual appearance.

Miranda has no detectable atmosphere and no magnetic field. Moons of Saturn, Uranus, & Neptune Moons of Saturn, Uranus, & Neptune Summary: The moons of Saturn, Uranus and Neptune range in size, though most are small compared to Jupiter's moons. Titan, the largest in this group, has an atmosphere and liquid lakes. Sections: Titan: What lies beneath the smog? Titan Unlike most other moons in our solar system, Titan has a very thick atmosphere that hides its surface from view. Chemicals in the atmosphere give Titan its reddish color. Titan's atmospheric composition: 90% nitrogen 10% mixture of argon, methane, ethane and other hydrogen compounds Despite its distance from the Sun, Titan's surface temperature is slightly warmer than it otherwise would be due to the greenhouse effect. This is the same process that traps heat on Earth. Some scientists believe Titan's current environmental status may be similar to that of Earth's before life formed. During the formation of the solar system, Titan formed past the frost line where temperatures in the solar nebula were cold enough for methane, ammonia and water to condense into ice. Titan is composed mostly of ices, including methane and ammonia ice.

Some of this ice sublimated long ago to form an atmosphere on Titan. Over billions of years, solar ultraviolet light broke apart the ammonia molecules into nitrogen and hydrogen. The lighter hydrogen escaped from the atmosphere but the heavier nitrogen molecules remained and accumulated to give Titan its nitrogen atmosphere. SHOW ME THE MATH Titan was recently visited by the Huygens probe , which landed successfully on the moon's mountainous surface after being released from the Cassini spacecraft in 2004. The Huygens probe sent back the first real images of Titan's mysterious surface, and scientists are still analyzing the data. Saturn's Medium-Size Moons (300 — 1,500 km in diameter) Saturn has 6 medium-size moons. In order of increasing distance from the planet, they are: Mimas Rhea Iapetus All are heavily cratered, indicating generally ancient surfaces, but each shows evidence of past geological activity. The geological activity may seem surprising when we consider how small these moons are; all are considerably smaller than the Galilean moons. Enceladus, with its grooved terrain, is barely 500 km across (small enough to fit inside Colorado).

In fact, the geological activity is probably a demonstration of the effectiveness of low temperature icy geology. Icy combinations of water, ammonia and methane can melt, deform and flow at remarkably low temperatures, producing a variety of volcanic and tectonic features. The surface of Enceladus shows signs of intense recent geologic activity. The Cassini spacecraft passed by the moon in 2005 and returned images showing ice geysers erupting from the surface. The material spewed out from these eruptions is a primary cause of Saturn's E-ring. MOONS OF URANUS Uranus has 27 known moons, all of which are named after characters from the writings of William Shakespeare and Alexander Pope. Uranus' medium-size moons (300 — 1,500 km in diameter) 5 medium-size moons orbit Uranus (from innermost to outermost): Miranda Titania Oberon Uranus' medium-size moons are made of ice and rock. Like other objects that formed far from the Sun, the ice is made up of ammonia, methane and water. These moons pose several puzzles.

Ariel and Umbriel are about the same size and density, but Ariel's young features indicate volcanic and tectonic activity, while Umbriel's largely cratered, uniform surface implies a lack of geologic activity. Titania and Oberon are also very close in radius, but show different levels of geologic activity. The faults on Titania indicate internal forces while Oberon's heavily cratered, icy surface shows few signs of movement. A Canyon on Miranda (click to enlarge) Voyager 2 came closest to Uranus' smallest moon, Miranda, as it passed by on its way to Neptune. The features on Miranda's surface are different from other jovian moons. With a mixture of old and new surfaces, Miranda shows relatively few craters but has a number of canyons up to 12 miles deep. Due to Miranda's odd surface features, scientists spectulate that there is an additional source of heat, such as tidal heating. The cliff walls seen in the inset are higher than those of the Grand Canyon on Earth. Uranus' Small Moons (click to enlarge) Uranus' small moons Uranus' smallest moons are its innermost satellites. Portia heads a group of 8 inner satellites.

The Portia Group consists of Bianca, Cressida, Desdemona, Juliet, Rosalind, Cupid, Belinda and Perdita. The Portian orbit is slowly decaying due to tidal deceleration and may one day either break apart to form a planetary ring or could potentially collide with Uranus. Orbits of the other satellites in the Portia Group have a similar fate. (click to enlarge) Triton: The backward moon of Neptune Voyager 2 discovered many of Neptune's moons in 1989, and took pictures revealing many previously unknown properties of Triton. Triton's icy, spherical surface reflects so much of the sunlight it receives that it is the coldest world in the solar system. Triton is the only moon in the solar system with a retrograde orbit. This, along with Triton's high inclination relative to Neptune's equator, suggests that Triton may have been captured from interplanetary space. The surface of Triton Photos of Triton show a strange surface shaped by more than just impact cratering, although its many undisturbed craters suggest that major geologic activity has subsided. Regions on Titan's surface show evidence of past volcanic and tectonic activity.

The internal heat source for Triton's geologic activity is not known, but it may involve tidal heating. The sublimation of surface ices creates a thin, hazy atmosphere on Triton made mostly of Nitrogen. The atmosphere creates wind streaks on the surface, and unknown processes pump unusual plumes of gas and particles into the atmosphere. The Mystery of Miranda, Uranus' Weirdest Moon, Has Been Explained SHARE NASA High-resolution image of the surface of Miranda, one of Uranus' largest moons, taken from the Voyager 2 spacecraft We already knew Miranda, one of Uranus' five major moons, has "one of the strangest and most varied landscapes among extraterrestrial bodies." Now, we (probably) know why The first and only space probe ever to visit the planet Uranus timed its encounter very badly from a public-relations perspective. Voyager 2 zipped past the solar system’s seventh planet on Jan. 24, 1986; four days later, the shuttle Challenger exploded in flames . And suddenly, far-off Uranus and its retinue of moons didn’t seem so important anymore.

Yet the images Voyager took during that overshadowed encounter have continued to intrigue planetary scientists ever since — and that’s especially true when it comes to Miranda, one of the planet’s five main moons. Its surface, U.S. Geological Survey astrogeologist Laurence Soderblom told TIME shortly after the encounter, “is a bizarre hybrid,” while NASA describes Miranda as having “one of the strangest and most varied landscapes among extraterrestrial bodies.” Perhaps the strangest features of all are Miranda’s three visible “coronae” — relatively crater-free regions marked by ridges and valleys and slapped onto the surface “like mismatched patches on a moth-eaten coat,” in NASA’s words. But now, nearly three decades after they were found, Miranda’s coronae may have an explanation at last. Writing in the journal Geology, Brown University planetary scientists Noah Hammond and Amy Barr argue that these odd scraps of terrain come from ancient hot spots in the moon’s 100-mile-thick crust of ice. “Despite being incredible cold,” says Hammond, ” there’s a lot of geologic activity on this moon.” Geology on the frigid moons of the outer solar system itself isn’t such big news these days.

Scientists have spotted volcanoes on Jupiter’s moon Io , ice geysers on Saturn’s moon Enceladus , lakes on Titan , plate tectonics on Europa and more. But to have geology, you need some source of heat, and there just doesn’t seem to be one for Miranda, which is deep-frozen to about –350°F. There’s no heat source now, anyway. But Miranda’s orbit is unusually tilted with respect to Uranus’ equator — its “inclination,” as astronomers call it, is about 10 times greater than that of the planet’s other major moons. One way that could have come about is if Miranda’s orbit was originally very eccentric, or elongated. That would have brought it into close encounters with other moons, which could have relocated into a tilted orbit. If Miranda’s orbit really was elongated, the moon would have been squeezed and stretched by the tidal effect of Uranus’ gravity, and, just like a rubber ball squeezed in your hand, it would have heated up a bit. And that rising heat would have made the ice itself flow very, very slowly upward — a process physicists call convection.

Hammond and Barr created a computer model of that flow, and sure enough, he says, “we were able to show that if shell is convecting, it naturally produces four upwellings.” Since it’s just a model, it can’t simulate the actual moon precisely, but it’s definitely in the ballpark of what Voyager saw. Each upwelling of ice would have tried to spread as it reached the surface, and crinkled, accordion-fashion, into the ridges and valleys that characterize the coronae. The fact that these regions are relatively crater-free fits right in: new ice flowing out from the interior would have to sit on the surface for a long time to match the cratering of the surrounding areas. The coronae can’t be more than a few hundred million years old — peanuts compared with the rest of the surface, which dates back billions of years, and consistent, Hammond says, with the fact that Miranda probably gained its tilt and lost its heat generation about that long ago. It all hangs together — but since it’s based on a handful of images taken nearly 29 years ago that only show Miranda’s southern hemisphere, it may be hard to be proved definitively.

Planetary scientists have a far richer set of observations for the moons of Jupiter and Saturn, where the Galileo and Cassini probes respectively stuck around snapping photos for years rather than flying by (and Cassini is still going strong). Unfortunately, while scientists are contemplating return missions to Jupiter and Saturn, nobody’s got plans to revisit Uranus. Which leaves Hammond and Barr’s theory of where the coronae came from in the “convincing but not definitive” realm. Hammond is absolutely definitive about one thing, however. “Miranda,” he says, “is a really cool moon.” Solar System : Uranus Images Uranus' Moons Uranus, the seventh planet of the Solar System, has 27 known moons, all of which are named after characters from the works of William Shakespeare and Alexander Pope. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the remaining spherical moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda).

The remaining moons were discovered after 1985, either during the Voyager 2 flyby mission or with the aid of advanced ground-based telescopes. Uranian moons are divided into three groups: thirteen inner moons, five major moons, and nine irregular moons. The inner moons are small dark bodies that share common properties and origins with the planet's rings. The five major moons are massive enough to have achieved hydrostatic equilibrium, and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces. The largest of these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about 20 times less massive than Earth's Moon. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at great distances from the planet. Oberon and Titania (king and queen of the fairies) are the largest Uranian moons, and were first to be discovered - by William Herschel in 1787. William Lassell, who had been first to see a moon orbiting Neptune, discovered the next two, Ariel and Umbriel.

Nearly a century passed before Gerard Kuiper found Miranda in 1948. And that was it until a NASA robot made it to distant Uranus. Astronomers using the Hubble Space Telescope and improved ground-based telescopes have raised the total to 27 known moons. Spotting the post-Voyager moons is an impressive feat. They're tiny - as little as 12-16 km (8-10 miles) across, and blacker than asphalt. And of course, they're nearly 3 billion miles away. All of Uranus's inner moons (those observed by Voyager 2) appear to be roughly half water ice and half rock. The composition of the moons outside the orbit of Oberon remains unknown, but they are likely captured asteroids.

Question: Which planet in the solar system has moons called Titania and Miranda
Answer: Uranus